1. Field
This invention relates to an improved typewriter mechanism, and more particularly, to an adjustable print mechanism to facilitate print line visibility.
2. Description of the Prior Art
Prior art typewriter devices have included print mechanisms which are moved from a rest position to a printing position. When the print mechanism is located at its rest position, away from the print receiving surface, the operator of the typewriter can readily view the line of print currently being printed (print line) since the print mechanism is generally located sufficiently far from the print receiving surface to prevent it from blocking the operator's view of the print line. Since the advent of the automatic typewriter, it has become desirable to increase the print out speed of the typewriter so that previously keyed information which has been captured on a secondary media such as magnetic tape, can be rapidly printed under operator control at a rate exceeding normal keyboarding rates. In order to increase the printout speed, it has been necessary to utilize single element printing mechanisms in contradistinction to individually mounted print elements such as typebars or the like so that characters may rapidly be selected without the individually mounted mechanisms interfering with one another. Further, it has been necessary to locate the printing element in close proximity to the print receiving platen to reduce the distance travelled by the print element and hence reduce the printing time. Location of the single element printing mechanism which includes a complete character set adjacent the print line generally interferes with the operator's view of the print line. The viewability problem is further complicated by the wide variety of viewing positions assumed by different machine operators.
Various prior art devices have been constructed to rotatably adjust the entire typewriting mechanism with respect to the operator's position to enhance operator viewability of the print line. An example of such a prior art device is described in the above referred to U.S. Pat. No. 3,830,352. There, the entire printer including the single element printing mechanism and the platen may be adjusted with respect to an assumed operator position. While such an arrangement provides a versatility of relationships between the operator position and the printer, it does not vary the location of the print line with respect to the curved platen on which the print receiving medium is located. Thus, as the entire printer is rotated in a first direction about its pivot, the print line becomes viewed at an acute angle wherein the character is viewed in a distorted fashion. As it is rotated in the second direction, the print element tends to block the print line viewability at the print point. Thus, while prior devices provide some degree of adjustment to facilitate different operator positions, they do so by adjusting the position of the entire printer and do not vary the location of the print line with respect to the print element.